Method of synchronising between three or more devices

ABSTRACT

Hitherto synchronisation of a number of devices has involved a large number of comparison steps between actual data or changes in data. Such comparison has potentially involved extensive redundant comparison steps. Another problem with existing synchronisation methods is that such synchronisation has been effected based upon the systems clocks defined by the devices. Those system clocks can be modified either intentionally or malevolently with disastrous consequences for subsequent synchronisation of the devices. Accordingly, the present invention relates to a method of synchronising between three or more devices, said method comprising: storing an indication of the device or devices involved in each synchronisation event; storing data changes received during a current synchronisation event together with the device submitting those changes; and applying the data changes subsequent to the stored synchronisation event for the or each device.

The present invention relates to a method of synchronising. Inparticular but not exclusively, the present invention relates tosynchronising data between devices such as computers, palm devices,personal digital assistants, music devices and mobile telephones. Thedata to be synchronised may comprise any data but commonly includescalendars, music files, photo files, emails, contact lists, bookmarksand any other such data. The present invention also encompassessynchronisation of applications. The present invention envisages thatsuch synchronisation may occur between applications on the same deviceor on different devices.

Hereinafter references to data includes data used by differentapplications and so the term devices includes applications stored on andrun by an electronic device. Moreover, synchronisation between devicesincludes synchronising data used by different applications on the sameelectronic device.

Hitherto, synchronisation of a number of devices has involved a largenumber of comparison steps between actual data or changes in data. Suchcomparison has potentially involved extensive redundant comparisonsteps. Another problem with the existing synchronisation methods is thatsuch synchronisation has been effected based on the systems clocksdefined by the devices. Those systems clocks can be modified eitherintentionally or malevolently with disastrous consequences forsubsequent synchronisation of the devices.

Synchronisation between devices may be effected in a number of ways.Once such system is disclosed in one of our co-pending U.S. patentapplications holding Ser. No. 10/453,051 filed on 2 Jun. 2003. A furthersystem is described in one of our other co-pending US patentapplications filed contemporaneously and the contents of which areincorporated herein by reference. However, to assist in the appreciationof a synchronisation method, a brief description will now be given withreference to FIG. 1. In FIG. 1, there is shown a first device 2 to besynchronised with a second device 4. The devices 2 and 4 are due forsynchronisation through a synchronisation engine 6. The devicescommunicate with the synchronisation engine 6 through conduits 8 and 10.Each of the conduits have a device specific area 8 a, 10 a, and astructured delta area 8 b and 10 b. Typically, the conduits also includea conduit store 14, only one of which is shown in connection withconduit 10.

The synchronisation engine 6 includes a synchroniser 12, mingler 16,Truth Table 20 and schema 22.

The conduits act as a liaison between the synchronisation engine and therespective device. The conduits principally translate data between thedevices data format and the synchronisation engine's canonical format.That is to say, the conduit receives data to be synchronised from therespective device and puts it into a canonical format and submits thesame to the synchronisation engine 6. Conversely, the conduits receivecanonical formatted data which is to be used to update the device andconverts the same into the format of the respective device.

The device specific areas 8 a, 10 a, of each of conduits contain astatic description of the devices' capabilities and indicates what typesof records or fields can be synchronised and the list of fields for eachrecord type which is supported by the respective device.

The structured deltas 8 b, 10 b retrieve the record or field which hasbeen modified in the device and compares it with that stored in theconduit store 14. The structured delta effects the comparison and passesthe change in the form known as a delta to the synchronisation engine 6.

The mingler 16 receives the stream of deltas from each device in turnthrough the respective conduit and updates the Truth Table 20. The TruthTable is an amalgamated copy of the records from all of the devicesinvolved in the synchronisation system. Thus, during synchronisation,each device is synchronised serially one at the time with the TruthTable and each record of the device being synchronised is synchronisedwith each record of the Truth Table. Hence, having obtained anamalgamation of all of the updated records from all of the devices, onlythen are the devices synchronised with the Truth Table, again serially.

Should any conflicts occur, then such conflicts are passed for conflictresolution through a user interface (not shown). The synchronisationengine 6 also includes a synchroniser for effecting the functions of themingler 16 and its affect on the Truth Table 20. In addition, thesynchroniser 12 manages the communications to and from the conduits 8,10. Finally, the schema 22 enables a user of the synchronisation systemto define the data to be synchronised, again through the user interface.

As discussed above, synchronisation of data involves a large number ofcomparison steps. The excessively large number of comparison steps canbe exacerbated when any device involved in the synchronisation system isabsent when the others are undergoing synchronisation.

Hitherto, synchronisation methods have been effected based upon thesystems clocks defined by the devices. As noted earlier, those systemsclocks can be modified either intentionally or malevolently. Thus, somedevices, whose systems clocks have been changed, may be synchronisedneedlessly or, indeed, some data may not be included in thesynchronisation.

Thus, the present invention seeks to improve methods of synchronising byoptimally identifying only those comparison steps which need to be made.Accordingly, the present invention relates to a method of synchronisingbetween three or more devices, said method comprising:

-   -   storing an indication of the device or devices involved in each        synchronisation event;    -   storing data changes received during a current synchronisation        event together with the device submitting those changes; and    -   applying the data changes subsequent to the stored        synchronisation event for the or each device.

Embodiments of the present invention will now be described by way offurther example only and with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic diagram of a synchronisation system as disclosedin our co-pending application filed contemporaneously;

FIG. 2 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 3 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 4 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 5 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 6 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 7 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 8 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 9 is a schematic diagram of an Administration Table and Truth Tablefor effecting the method of synchronising data according to the presentinvention;

FIG. 10 is a schematic diagram of an Administration Table and TruthTable for effecting the method of synchronising data according to thepresent invention;

FIG. 11 is a schematic diagram of an Administration Table and TruthTable for effecting the method of synchronising data according to thepresent invention;

FIG. 13 is a schematic diagram of an Administration Table and TruthTable for effecting the method of synchronising data according to thepresent invention; and

FIG. 14 is a schematic diagram of a Truth Attribute Table and TruthRelationship Table to illustrate in more detail the Truth Table includedin the method of synchronising data according to the present invention.

The present invention relates to a method of synchronising whichincludes not only storing the actual data which has been changed butalso together with logging the synchronisation events and the devicesinvolved in those events. Hence, as shown in FIG. 2, data is acquired inan Administration Table indicating which devices are involved in thesynchronisation system. In this case, the devices indicated are a phone,palm device, home computer and work computer. The synchronisation eventsare indicated in the column generation. In this case, thesynchronisation system has been initialised such that there have been nosynchronisation events. Accordingly, for each device, the generationindicated is zero.

FIG. 2 also illustrates the Truth Table which provides a format forstoring the data being changed under the column Datum. Thesynchronisation events are stored in one or two columns, ModifyGeneration and Add Generation. Modify Generation events involve wherethe field or record has already existed and the change involves amodification of that data. Conversely, Add Generation notes those newfields or records to be added. Finally, the Truth Table also indicateswhich device or client has provided the change under the column Client.Since FIG. 2 refers to the initialised state of the synchronisationsystem, there is no data in the Truth Table.

FIG. 3 demonstrates the type of data which may be stored after the firstsynchronisation event. In this case, the phone in the synchronisationsystem is the only one involved in the synchronisation event. The phonesubmits two new records or fields X and Y. Hence, in the AdministrationTable, the device or client phone is indicated as being involved in thefirst synchronisation event. In the Truth Table the data X and Y isindicated as being added in synchronisation event 1 by the device orclient phone.

In FIG. 4, the phone also instigates the second synchronisation event byadding datum Z. Hence, the Administration Table is updated to indicatethat the phone is involved in the second synchronisation event, and thatthe Truth Table has added Datum Z in the second generation. In thiscase, it is necessary to retain both the previously added datums X and Yfrom the first synchronisation event since the other devices or clientsin the system, the palm device, home computer and work computer, havenot been advised of the changes involved in the first synchronisationevent.

In FIG. 5, all of the devices or clients are present during the thirdsynchronisation event. Hence, the Administration Table indicates all ofthe clients as being present in the third synchronisation event. In thethird synchronising event, no data changes have occurred. Hence, noadditional datum is indicated in the Truth Table. However, since thepalm device, home computer and work computer were not present during thefirst and second synchronisation events, these devices are updated fromthe Truth Table with the changes to the X, Y and Z datum. Since thephone submitted the datum changes X, Y and Z during the first and secondsynchronisation events, there is no need to update the phone with thedatum X, Y and Z.

Since all of the clients were present during the third synchronisationevent and that all of the clients were updated with all of the changesindicated in the Truth Table, then it is possible to delete thosechanges from the Truth Table. This is shown in FIG. 6. TheAdministration Table logs that each of the clients were each lastinvolved in the third synchronisation event but since all of the deviceswere updated with all of the changes up to the third synchronisationevent, those changes may be deleted from the Truth Table and the TruthTable is blank.

FIG. 7 illustrates the fourth synchronisation event, whereby the phoneadds a new record A.

FIG. 8 illustrates the palm device in the fifth synchronisation event,adding a new record B. The palm device, since it was not involved in thefourth synchronisation event, is updated with the new datum A which wassubmitted by the phone in the fourth synchronisation event. However, thepalm device is not updated with datum B since the palm device submittedthe datum in the fifth synchronisation event. Moreover, the phone is notupdated with datum B since it was last present during the fourthsynchronisation event and is not present for the fifth synchronisationevent. Accordingly, the phone includes the new datum A but not the newdatum B. The palm device includes both datum A and B. The home and workcomputers include neither datum A or B.

In FIG. 9, the phone in the sixth synchronisation event adds the newdatum C. Moreover, the phone is updated with the new datum B submittedin the fifth synchronisation event from the palm device.

In FIG. 10, the phone, palm device and home computer are all presentduring the seventh synchronisation event which adds datum D on the homecomputer. Since the phone was present during the sixth synchronisationevent, the phone only needs to be updated with datum D. The palm devicewas previously present during the fifth synchronisation event and sowill be updated with datum C and D. The home computer, since it was onlypreviously present during the third synchronisation event, is updatedwith datum A, B and C. However, the home computer is not updated withdatum D since the home computer submitted datum D itself. Finally, thework computer is not updated since it was not present during the seventhsynchronisation event and was previously only present during the thirdsynchronisation event. Accordingly, any changes since the thirdsynchronisation event must be retained in the Truth Table.

In FIG. 11, all devices in the synchronisation system are present duringthe eighth synchronisation event. Accordingly, the work computer isupdated with datum A, B, C and D. Since no further datum changes weresubmitted by any of the devices, the Truth Table can then be cleared ofsuch changes. This is shown in FIG. 11.

In FIG. 12, during the ninth synchronisation event, the phone submits amodification of datum G′.

In FIG. 13, the work computer submits a further modification to datumG″. The datum G is thus modified by two different devices. Accordingly,the synchronisation engine seeks in the first instance to identifywhether any conflict exists. Various scenarios may be encountered duringsuch identification:

-   -   The two devices may submit the same change. Thus, if G′ equals        G″, then clearly there is no difference between the datum and        hence no conflict exists.    -   If the datum comprises a field of a record as opposed to a        record per se, then G′ may relate to one field, whereas G″ may        relate another field of the same record. Hence, again there        would appear to be no conflict.    -   If the datum comprises a whole record, then G′ will not equal G″        so that a conflict will be found to exist. However, the schema        may include rules for defining whether such conflicts may be        overlooked or whether they should be passed for conflict        resolution. Such rules may include whether the datum involves an        identity key such that all conflicts submitted to the user for        resolution.

In any case, having identified whether a conflict exists and havingresolved that conflict, the Truth Table is then updated with theresolved conflict. Subsequent synchronisation events and updating stepsare then effected, as discussed previously.

As a consequence of storing the actual data changes together with thelog of synchronisation events and the devices involved, it is possibleto optimally identify only those comparison steps which need to beeffected. Moreover, since the base line upon which the synchronisationmethod relies is the log of synchronisation events and clients involved,any modification of the systems clocks will not affect the optimalefficiency of the synchronisation method.

The present invention is applicable to any known synchronisation system,device or data. In particular, the synchronisation method according tothe present invention is particularly useful to not only attribute databut also relationship data. In the example where the data comprisescontact lists, a persons contact details may include home telephonenumber, work telephone number and mobile telephone number as well asvarious addresses including e-mail addresses of both work and home, andpostal address and work address. Each of the contact details would beconsidered a field, whereas all of the contact details for a particularperson would be considered the record. Either the field or the recordmay be considered attribute data. The contact list may also include therelationships between that person and other persons held in the contactlist. This could include the fact that the first person is a brother toa second person. A third person's details may also be given togetherwith the relationship that he is a father to both the first and secondperson. Any types of relationships may be given, not just relativerelationships but also relationship information such as girlfriend,boyfriend or partner, work colleague or other contact relationships.

FIG. 14 indicates the type of Truth Table that may be held whensynchronising both attribute data and also relationship data. In thiscase, during synchronisation event 11, the work computer submitsmodifications to record number 1 in relation to datum fields S″ and Q.The home computer during the synchronisation event 12 submits amodification to record number 2, including the datum field T.

The Relationship Table includes details of the relationship from sourcerecord number 1 to target record number 2, to indicate that therelationship is a parent relationship. Conversely, record number 2 isindicated as having a relationship as a child from record number 2 toboth record number 1 and record number 3.

In FIG. 14, the Administration Table has not been included toconcentrate on the Truth Table. Moreover, the Truth Attribute Tabledefines the datum as a field level and also includes a record number.This is not necessarily required according to the present invention butdoes assist in identifying all of the changes to a particular record. Inall other respects, the Truth Tables indicated in FIG. 14 are merely amodification and extension of the Truth Tables indicated in the previousfigures.

The foregoing description has been given by way of example only and itwill be appreciated by a person skilled in the art that modificationscan be made without departing from the scope of the present invention.

1. A method of synchronising between three or more devices, said methodcomprising: storing an indication of the device or devices involved ineach synchronisation event; storing data changes received during acurrent synchronisation event together with the device submitting thosechanges; and applying the data changes subsequent to the storedsynchronisation event for the or each device.
 2. A method ofsynchronising as claimed in claim 1, further comprising identifying datachanges prior to storing data changes.
 3. A method of synchronising asclaimed in claim 1 or 2, in which said applying the data changes doesnot include the data changes submitted by the device during a currentsynchronisation event.
 4. A method of synchronising as claimed in claim1, in which said data changes include adding new data, deleting data oradding data.
 5. A method of synchronising as claimed in claim 1, inwhich said data comprises attribute and/or relationship data.
 6. Amethod of synchronising as claimed in claim 1, further comprising:identifying any stored data changes which have been applied to alldevices; and deleting said data changes from said store of stored datachanges.
 7. A method of synchronisation as claimed in claim 1, in whichsaid data comprises attribute and/or relationship data.
 8. A method ofsynchronisation as claimed in claim 1, in which said devices includesapplications stored on or run by electronic devices.
 9. A method ofsynchronisation as claimed in claim 8, in which said devices compriseapplications stored on or run by the same electronic device.
 10. Amethod of synchronisation as claimed in claim 8 or 9, in which saidelectronic devices include computers, palm devices, personal digitalassistants, music devices and mobile telephones.